Engineering notes
Pipe temperature: strap-on, immersion, or a well
A strap-on head is slow when the insulation is thick. Immersion or a well sees the water. Match NTC or 4–20 mA to the DDC.
The drawing says “temperature sensor on CHW pipe”. Stores issue a strap-on so nobody drills the pipe. The head sits outside the insulation and reads the jacket — the chilled-water valve hunts all afternoon. If the consultant wrote immersion, you need a well, enough insertion, a gland that does not drip.
Strap-on is fine on a small bare pipe when you only need “is it hot”. AHUs, main valves, efficiency points: immersion. The output must match the cabinet — NTC on a resistance input, 4–20 mA on a current input. Do not put a PT100 on a 10 kΩ NTC terminal.
State pipe diameter and insulation thickness when you ask. NTC, PT100, PT1000